The CASPAR homeless shelter, a low-slung brick building, crouches on Albany Street in Cambridge. When percussionist Jennie Dorris wheels her marimba through the front door, half of a large central room has been cleared, and a line of grizzled men sits at a long row of tables, watching.

An enthusiastic older man in a Boston Strong T-shirt marches up, introducing himself as Danny. “Finally, the marimba’s here!” he exclaims, grinning. “I wait all year for this.”

For many smaller performing arts groups, attracting and retaining audiences is at the front of organizers’ minds. But not for Shelter Music Boston. In fact, it’s sometimes better if its audience doesn’t come back: This ensemble is dedicated to playing at homeless shelters and recovery centers.

Advertisement

“What compels me is to take music where it’s needed and treat everyone with respect,” says founder Julie Leven, a violinist. This year, its eighth, Shelter Music Boston has mounted scores of concerts in shelters throughout the Greater Boston area, including a full schedule in the days leading up to Christmas.

It’s not the only music group focusing on the homeless around Boston. Eureka Ensemble, whose mission is to nurture social change, launched a Women’s Chorus that welcomes women experiencing severe poverty and homelessness. With both groups, musical efforts have had a profound effect for many among the vulnerable populations they seek to serve.

Eureka’s most ambitious project, according to cofounder and conductor Kristo Kondakci, was a commissioned composition, Stephanie Ann Boyd’s “Sheltering Voices.” Auditions for choral fellowships for women were held at Pine Street Inn and Women’s Lunch Place, says Kondakci, a recent graduate of New England Conservatory who has worked with the homeless since his student days at Boston College High School. Around 15 took part.

Carrie Jaynes and Rottisha Mewborn are friends who met at Pine Street Inn. When they saw the audition sign-up sheet, they were initially skeptical, they say — they’re used to well-meaning outsiders putting in a few hours and then disappearing.

Advertisement

But they went to the audition in March, in a room where the heater was going haywire. To cool it down, Kondakci threw open the door of a nearby freezer.

And that, Mewborn says, put them at ease. “The ingenuity in that one motion. In that moment, it made [Kondakci] seem grounded,” she says. “Not ‘Oh, no! Who do we call, maintenance?’ Nope!”

As Eureka Fellows, Jaynes and Mewborn rehearsed weekly with Kondakci, learning “Sheltering Voices.” They were never treated as anything less than important and independent, they say.

“We became so desensitized at Pine Street that we forgot how we can be treated like a normal person,” says Jaynes. At the rehearsals, she says, “we knew that we were in this together. We knew that we were all right . . . we could be human again. We could show emotion and not be judged if we cried, or laughed, or showed a softer side of us.”

“People don’t realize how much mental illness there is in shelters,” says Rottisha Mewborn. But music “pulls things together for that one moment.”(Katherine Taylor for The Boston Globe)

Jaynes and Mewborn have also attended Shelter Music Boston concerts, and they praised the music and the change in atmosphere that it brings. “People don’t realize how much mental illness there is in shelters,” Mewborn says. Every day at Pine Street, she says, she sees women intensely berating themselves as they go about their day, but that stops when the music starts: “It’s spreading some sort of gel in their minds, and pulls things together for that one moment.”

Advertisement

A host of scientific studies have found physical and mental benefits linked to classical music, including the release of dopamine at peak emotional moments. Shelter staff say that after Shelter Music Boston concerts, the atmosphere is more peaceful, and nights are more restful, notes Leven, who also plays with Handel and Haydn Society and the Boston Pops Esplanade Orchestra.

Shelter Music also drew on homeless people’s creative input for a world premiere: “Water for My Soul,” in August. Composers Yu-Hui Chang, Francine Trester, and Danielle Williams worked on the piece, which features words taken from comments on forms Shelter Music collects after each concert. The title came from one shelter guest who wrote about a concert: “The music was water for my soul when it was thirsty.”

“What compels me is to take music where it’s needed and treat everyone with respect,” says Shelter Music Boston founder Julie Leven, a violinist (foreground), here with Shelter Music players rehearsing for a world premiere. Clockwise from left: Cellist Javiar Caballero, violinist Rebecca Strauss, and singers Carrie Cheron, Jessica Petrus, and Rashaun Campbell.(John Tlumacki/Globe Staff)

The piece also incorporated musical ideas from shelter guests who attended workshops. “The idea was that we would sort of be their musical jukebox,” says Dorris, a longtime Shelter Music player. “It was our job to . . . show them what their ideas sounded like on our different instruments.”

At the CASPAR shelter concert in Cambridge last August, the room is noisy, with the hubbub of many conversations bouncing off the concrete walls. But as soon as the first piece starts, a sense of calm descends.

“This premiere made me feel the strength of music, what it can do to people. It’s not always so obvious in a normal concert hall,” composer Yu-Hui Chang comments afterward. “But in places like this, you really can tell how people relax.”

Advertisement

When the young baritone RaShaun Campbell steps to the front for his solo, a slender black male guest leans across a table toward Carrie Eldridge-Dickson, Shelter Music’s managing director.

“Is it, like, opera?” he asks. Eldridge-Dickson replies yes, there will be singing.

“Can I rap to it?” he asks. Seeing Eldridge-Dickson’s bewildered expression, he bursts into laughter. “Just [expletive] with you.”

The concert is twice interrupted when guests behave aggressively, and Leven immediately cedes the floor to the staff each time. But the performers keep things moving along.

Two women guests said “they actually listen to it in their head again before they go to sleep,” volunteer Sherry Grossman tells Chang and Leven outside afterward.

At a recent CASPAR concert by Shelter Music, freezing winds blew along Cambridge’s streets, but musical warmth spread inside. One guest, Kevin J. Merrill II, said, “I love it when these guys come in. They brighten up the place, they give us hope. It’s a great experience, especially at a time like this.”

As for the Eureka fellowships, Jaynes and Mewborn say their experiences were powerful. “Having Kristo say ‘We’ll get you there no matter what’ built up our trust and our safety,” Mewborn says. Because Pine Street Inn has a daily lottery, she explains, she never knows if she’ll have a bed to sleep in each night. There’s little in her life she can truly count on. “So just having this little safety — even if things are going crazy out here, we can get there — it’s amazing.”

Advertisement

When people realize they’re homeless, plenty want to give them “dime advice,” says Mewborn. “Go get a job! And . . . ”

“And by the way, come to my church!” says Mewborn. “But Kristo never did that for us.” She turns towards Kondakci. “Every time you left us on the street, we’d always be smiling.”

Eureka’s Fellows received private voice lessons and a $300 stipend. The oldest fellow, 82-year-old Lidiya, had been musically trained in her native Russia, but most of the fellows could not read music. “They would come into the rehearsal wearing earphones, listening to [their parts] over and over,” Kondakci says.

“Sheltering Voices” includes clusters of ethereal dissonances and wandering melodies. “We didn’t think it was a real song until the orchestra came,” Jaynes says, laughing.

The world premiere, featuring the Eureka Fellows, volunteers from Chorus Pro Musica, and soprano Angel Azzarra, took place at Church of the Covenant on May 12. Eureka had worked with shelters to reserve beds for the fellows who needed them. For that one night only, they knew where they could sleep.

Eureka’s Women’s Chorus, founded by Kondakci and retired businessman and longtime choral singer David McCue, grew out of the fellowship program. “We’re learning what draws people and what draws them to come back,” McCue says. “What kind of repertoire to sing and what kind of training to give them.”

One morning in September, the spire of Church of the Covenant pierces the sky on the corner of Newbury and Berkeley streets. At the Women’s Lunch Place day shelter in the basement, guests get meals, do laundry, and use the library and computers. Upstairs in the sanctuary, singers trickle in for practice. Kondakci chats with one singer about meditation and qi gong while some get coffee and water from a small table.

Lidiya now has an apartment after sleeping in shelters for three years. When Kondakci starts playing a peppy melody on the piano, she dances over to the small group, joining in for the first tune. “Wake me/ Shake me/ Don’t let me sleep too late!” they belt, chorusmaster Ismael Sandoval conducting.

They do warm-ups: lip trills, scales, “I love to sing!” on ascending arpeggios. The book is stacked with songs: “Wade in the Water,” “Somewhere Over the Rainbow,” a few African folk songs, “Dona Nobis Pacem,” and “Va, pensiero,” the longing chorus of exiles from Verdi’s opera “Nabucco.”

“Amazing Grace” is in the repertoire, too. After one run-through, Sandoval announces that now the singers will each take a turn conducting the group. He asks for a first volunteer, and tells everyone to watch how she leads.

Lidiya steps to the front. As she raises her arms, the sanctuary fills with sunlight.

Zoë Madonna can be reached at zoe.madonna@globe.com. Follow her on Twitter @knitandlisten. Madonna’s work is supported by the Rubin Institute for Music Criticism, San Francisco Conservatory of Music, and Ann and Gordon Getty Foundation.